90128169 has 24 divisors (see below), whose sum is σ = 138251880. Its totient is φ = 56383488.

The previous prime is 90128147. The next prime is 90128179. The reversal of 90128169 is 96182109.

It can be written as a sum of positive squares in 4 ways, for example, as 56430144 + 33698025 = 7512^2 + 5805^2 .

It is not a de Polignac number, because 90128169 - 2⁸ = 90127913 is a prime.

It is a super-2 number, since 2×90128169² = 16246173694585122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (90128179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69277 + ... + 70565.

It is an arithmetic number, because the mean of its divisors is an integer number (5760495).

Almost surely, 2^90128169 is an apocalyptic number.

It is an amenable number.

90128169 is a deficient number, since it is larger than the sum of its proper divisors (48123711).

90128169 is a wasteful number, since it uses less digits than its factorization.

90128169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1769 (or 1766 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 90128169 is about 9493.5856766556. The cubic root of 90128169 is about 448.3531060348.

The spelling of 90128169 in words is "ninety million, one hundred twenty-eight thousand, one hundred sixty-nine".